Tag: spiders

Tiny spiders have enormous brains, so big the neurons spill into their legs, causing the spiderlings of some species to bulge like overstuffed brain-bags (although the bump fades with adulthood). In some small arachnids this extended brain—really just a tangled mass of nerves—takes up almost 80 percent of the animal’s body cavity, and about a quarter the mass of its legs. Talk about thinking on your feet. The percentage of space devoted to cognition dwarfs that of humans, whose brains take up two to three percent of the body. It also trumps the setup of minute beetles and ants, whose brains make up only 15 percent of their weight. These insights come from a study published recently in the journal Arthropod Structure and Development, which set out to explain why small spiders are basically as adept as large spiders when it comes to completing relatively complex tasks like building webs. These massive distributed brains, it turns out, may be the answer.

For male black widow spiders, standing at just a quarter of the size of their mates, sex involves a very real danger: females of the species have no qualms about turning cannibalistic if they’re hungry after getting down and dirty. But it seems that it’s more than just a game of chance for horny male spiders. Researchers at Arizona State University have now learned that simply walking on the webs of female spiders can provide males with chemical cues telling them if their potential mates are ravenous enough to eat them.

Life is uncertain–eat the head first. That’s the philosophy behind every meal a Zodarian spider eats, and there’s a strategy behind it. Consuming certain body parts first ensures the spiders consume the maximum concentration of vital nutrients during the meal, according to research published in the journal Animal Behavior. LiveScience reports:

“When chowing down on ants, the spiders consistently began with the protein-packed front parts before getting to the fattier hind segment, called a gaster or abdomen. The picky eating seemed to pay off: Spiders reared on just front-end ant pieces grew faster and bigger, and they lived longer than those served only gasters or even whole ants.”

In what sounds like a medical mystery suitable for Dr. House, doctors in Leeds couldn’t figure out why antibiotic treatment wasn’t working for a 29-year-old British man with a three week history of a red, watery, and light-sensitive eye. As the doctors soon discovered, this wasn’t your normal case of pink eye, according to the Los Angeles Times:

Once examined under high magnification lenses, hair-like projections were spotted at varying depths within the cornea. When these details were discussed with the patient, he immediately recalled an incident that had preceded the onset of his symptoms. 3 weeks earlier, he had been cleaning the glass tank of his pet, a Chilean Rose tarantula. While his attention was focused on a stubborn stain, he sensed movement in the terrarium. He turned his head and found that the tarantula, which was in close proximity, had released “a mist of hairs” which hit his eyes and face.

It’s hard to believe a blast of projectile hairs to his eyeball slipped the patient’s mind.

In hindsight, protective goggles would have been a good investment considering that Chilean Rose tarantulas are known to launch their barbed hairs at attackers in self-defense. The hairs were too tiny to be removed by microforceps, so the spider owner is left with taking steroid eye drops to clear up his symptoms.

If you thought going to the club was bad, imagine having to dance in front of potential mates for over an hour and a half, lest they will eat you. Male Australian redback spiders, members of the black widow family, pay the ultimate price if their mating dance doesn’t impress.

Males, which are just 1 percent to 2 percent of a female’s body weight, dance about the web of a potential mate, plucking at the threads and sending out vibrations. Once the male redback has performed an adequate dance, the female will allow him to mount her and insert one of his two palps, or copulatory organs, into one of a pair of sperm storage organs. The male then somersaults to place its abdomen directly above his mate’s fangs. That’s perfect positioning for the female to begin devouring the male’s body.

To avoid being gobbled up by the female halfway through mating, males need to dance for 100 minutes, according to new research. But the dancing males better have a good internal clock. Females can’t determine the source of courtship, so if the dancer exceeds the optimal time, a slick male could sneak in a mate with the female while the dancer ends up alone on the web.

For a video of the life-or-death dance, click on over to the Discovery News.

A British paleobiologist thinks he’s found traces of the oldest spider web on record.

Millimeter-thin strands of the presumed web have remained trapped, Jurassic Park-style, in fossilized tree resin (better known as amber) for eons. An amateur fossil hunter stumbled upon the chunk of archaic amber on a beach in southern England.

Martin Brasier, the Oxford University scientist who examined the specimen under a microscope, estimates the encapsulated web dates back some 140 million years to the Cretaceous period. That’s in the heyday of the dinosaurs, well before they went extinct about 65 million years ago. Though not a full web, the preserved strands still form a circular pattern that resembles the orbs spun by modern-day arachnids the world over.

For the last ten years, two new species a week have been identified in the Greater Mekong, a swath of diverse ecosystems along the Mekong River in Southeast Asia. In a new World Wildlife Fund report [pdf], scientists say they have documented at least 1,068 new species since 1997.

These aren’t run-of-the-mill species, either. Take Desmoxytes purpurosea, a bubble-gum pink “dragon” millipede that looks like a Halloween prop. Scientists found the thumb-sized centipede just sitting around on rocks and palm trees. Its shocking pink color is actually a warning to would-be predators: get too close and they’ll have to contend with the deadly cyanide that the millipede secretes. This millipede won a spot in Arizona State University’s annual Top Ten New Species.

The new species also include 88 types of spiders. The report says the “most remarkable” of these is the colossal cave-dwelling Heteropoda maxima. With a legspan of 30 centimeters (12 inches), it is the largest huntsman spider in the world.

• Ever wanted to scratch-n-sniff Michael Phelps? The current issue of People features a special “Sexy Scents” section with “scratch-n-sniff” photos of hunky men and their preferred odors. (Is it chlorine?)

Male jumping spiders, known for their wicked dance moves (video), may have another trick for attracting mates: ultraviolet come-hither looks. The discovery, made by Jingjing Li from the Hubei University in China and published yesterday in Current Biology, is the first evidence that insects can detect UV-B rays.

UV-A rays can be detected by many insects, birds, fish, and mammals, but UV-B rays are more energetic than UV-A rays (which makes them perfect for giving us cancer and sunburns), and it had been assumed that no animals had the right equipment for detecting them.